Coasts
The sixth and final episode of The Blue Past, focusing on the coasts and beaches of the Mesozoic. Animals featured *''Cynodont'' *''Cryolophosaurus'' *''Atractosteus africanus'' *Cladocyclus *Retodus *''Spinosaurus'' *Asteracanthus *Carcharodontosaurus saharicus *Ichthyornithid *Leptocleidus *Retodus *Rugops *''Hesperornis'' *''Rhamphorhynchus'' *''Nanuqsaurus'' *''Edmontosaurus'' *Mosasaurus Plot Sequence One Sequence Two Sequence Three Sequence Four Those rivers hold much bigger animals than Atractosteus africanus. They also are home to a true giant, the largest carnivorous dinosaur that has ever existed. The top of a slender snout appears out of the murky water and the animal takes a breath, spraying salt from its nostrils as it does so. As the creature dives back into the water a massive, colorful sail cuts through the water’s surface. An Asteracanthus searches for clams and other bivalves in the muddy seafloor, just as a massive crocodile-like snout grabs the shark. The predator surfaces. This is a Spinosaurus aegyptiacus, by far the largest predatory dinosaur ever. But this theropod is different from most others. It hunts not on land, but in the water. The Spinosaurus climbs ashore, revealing its bizarre anatomy. The weirdest part are its legs, which are unusually short for an animal of this size. As if that wasn’t strange enough, its entire body is elongated. How does this creature even walk? The answer lies in its posture, Spinosaurus walks slightly more upright than other theropods and also keeps its neck coiled against its shoulders, like a heron, which shifts the center of gravity backward. However, on land, this animal is still quite clumsy and awkward. And at risk of attack. A Carcharodontosaurus, the largest predator of the Kem Kem, stalks the Spinosaurus, an easy target on land. However, it makes one big mistake, while watching its prey, rather than the ground, it steps on a fallen branch. The Spinosaurus is alerted to its presence and it belly slides off of the bank and into the water. The Carcharodontosaurus cannot follow, while it can swim it has no chance of catching the Spinosaurus, which swims off into the distance. It may be slow and clumsy on land, but in the water, Spinosaurus is king. A few miles out to sea, another Spinosaurus is swimming. Flocks of ichthyornithid birds fly overhead. Spinosaurus occasionally swim miles out into the open ocean, often to swim between islands. Because of this, several of the islands around North Africa now have small populations of Spinosaurus. A Leptocleidus glides through the water and catches a small fish. The Spinosaurus playfully swims after the Leptocleidus, slipping through the water like a sea lion. The Leptocleidus and Spinosaurus spiral around each other in the water as the setting sun casts a red glow over the sea. Back in the mangroves, a Spinosaurus has caught a huge Retodus. During this time of year, these fish are very common and so the Spinosaurus is being very wasteful. It only eats the brains and eggs and then discards its kill. Scavengers take advantage of this fact. An abelisaurid cautiously swims toward the Retodus carcass and drags it ashore. Though no other theropod in the Kem Kem spends as much time in the water as Spinosaurus, almost all of them depend on the fish of these mangroves in some way. Once the mangroves disappear, so will these specialized and amazing dinosaurs. Sequence Five Some animals that rely heavily on the ocean must come ashore to breed. On the coastal cliffs of the island of Germany, Rhamphorhynchus gather at twilight. The males select specific sites on the cliffs as territory, and send out clicks and calls to attract mates. Once the females arrive, they nuzzle and lick each other. Occasionally, they will nest on the coastal plains of sand instead, if the cliffs are too crowded, like they are now. Males lie on the sand and click for mates. Now, when the females arrive, they do the same ritual. But some males do not play fair. As an amorous couple bond, a big male leaps at the other male, and knocks him down. They spread their wings out and try to size each other up. They tackle and bite. Then, the fighting goes into the air. The intruder leaps up and our male follows. They dive bomb each other, right over the open ocean, trying to tear each others wing membranes and prevent them from flying anymore. This is a fight to the death. Eventually, our male lands a direct blow into his rivals wing, and tears a massive hole. The male flaps, but looses control, spiraling down into the water. He returns to his mate and they complete the ritual. Then, they mate. As night begins, the females leave their partners to lay their eggs. They lay one egg each, but for the next few weeks will lay an egg at least once a day. Some lay their eggs close to shore. Others, like our female, go far inland, and into the forests, where the soil is just perfect. To dig, they use a reversing of the quad launch. After a few large kicks, the female has dug a half metre deep trench. She then lays her eggs, and then buries them, before returning to her partner. However, not all will lay their eggs. An adult Sciurumimus watches in the forest, waiting for one to get close. A female is away from all the others, alone. And she's looking in the other direction, just perfect. The Sciurumimus moves his leg forward slightly, looks up to judge distance, and sits still briefly. Then, as she begins to dig, he lunges from the bushes and grabs her. She still struggles, but he snaps his jaws shut a few more times, before finally walking away with a meal. Some Rhamphorhynchus females on the coast and becoming agitated. They begin to fight over areas to lay their eggs. However, they make sure they only intimidate by expanding their wings, to avoid physical confrontation, before a competitor backs down. These are the worlds most common sea pterosaurs. Sequence Six Trivia *The Cretaceous North Africa sequence is split into two parts, the first focusing on Atractosteus africanus, and the second focusing on Spinosaurus. *The final sequence focuses on both Nanuqsaurus and Edmontosaurus.